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Turn a 3-Core AMD Phenom 2 into a 4-Core

By - Source: Tom's Hardware US | B 43 comments

We received word that a Korean hardware review site has managed to turn a triple-core Phenom II X3 710 into a 4 core CPU.

Apparently, the quick switcheroo requires a Biostar motherboard says the site, but customers boards that have the same BIOS options can try the same technique out. The BIOS option to enable the 4th core is called Advanced Clock Calibration, and when set to Auto, turns on the 4th core.

From our experience, when AMD or Intel ships a processor with a core disabled at manufacturing, it's because the disabled core isn't performing up to snuff with the other core(s). We'd be interested in knowing if users experience any bugs with the 4th core enabled.

The processor shows up with 4 cores in Windows, and according to benchmarks posted by the site, the 4th core had a real impact on scores. Those with 3-core Phenom II's, try this out!

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  • 0 Hide
    bustapr , February 23, 2009 5:37 PM
    I first thought of gatting a budget core 2 quad but this really sounds like more bang for the buck. That is if it has minimal bugs.
  • 3 Hide
    kyeana , February 23, 2009 5:43 PM
    hmm interesting. I wonder how that effects stability and overclocking?
  • 4 Hide
    scryer_360 , February 23, 2009 5:52 PM
    It worked! Just loaded a 710, and just like the article says, switching ACC to "Auto" on a biostar board now has me reading 4 cores on the bios loading screen.

    The thing is, in order to make the 3 core processor, AMD has to test a processor bad. With millions of the things running down the line, they are probably testing a few samples from a batch (this is industry practice right?). So if one is testing bad, they just take the whole batch down to three cores. That means others in a batch are still good. I wonder if the same isn't achievable with non-biostar boards?
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  • -7 Hide
    scryer_360 , February 23, 2009 5:57 PM
    Though, this has to happen to Intel as well. Why does AMD intentionally harm the bottom line by creating a product that fills no market, unless the product is priced way below the desired finish (that is, the only reason to buy a triple core is that it'd be cheaper than a four core, but AMD is making four cores into triple cores).
  • 8 Hide
    jsloan , February 23, 2009 5:59 PM
    like with video cards, because a manufacturer sells it with 3 cores actives does not mean the 4th won't work, it may and it may not.

    sometime they because of demand they are forced to ship what would have been 4 cores as 3 cores, but they don't want to lower their 4 core prices, but can't produce enough of them for the demand so they will quietly ship the good 4 core ones as 3 core ones. this happens.

    so people should try and then run extensive testing of the core. maybe it had a small flaw the results in periodic errors or errors only with certain operations. one just has to test, test, test.
  • 5 Hide
    leo2kp , February 23, 2009 6:04 PM
    scryer_360Though, this has to happen to Intel as well. Why does AMD intentionally harm the bottom line by creating a product that fills no market, unless the product is priced way below the desired finish (that is, the only reason to buy a triple core is that it'd be cheaper than a four core, but AMD is making four cores into triple cores).

    That would be true unless the 4th core is actually failing their tests. So instead of throwing the whole thing away, why not sell it as a 3-core for less? They end up making a lot more money that way because they're selling what they would otherwise call "garbage".
  • 0 Hide
    scryer_360 , February 23, 2009 6:38 PM
    leo2kp is right though: if the 4 core doesn't work, what would otherwise be trash you can at least get some money out of as a 3 core. Still, in order to satisfy 3 core demand, AMD must be taking batches that had a small failure rate (and remember, if the few samples per batch have a fail, that doesn't mean all the processors in the batch do), they would have to canabalize good 4 cores to make some 3 core chips as nessecary. Unless sales of three core chips are low enough to just use "scraps."
  • 3 Hide
    hellwig , February 23, 2009 6:42 PM
    How do you take a loss on something that you would otherwise throw away? At a minimum, selling X3's recoups some of that loss, assuming they don't actually make a profit off it, which I'm sure they do.

    Its the same way the Radeon 4870 and 4850 are the same chip, but the 4870 is higher-clocked and uses much faster GDDR5 memory. Re-tooling the production line is where the cost in incurred. The more products you can make out of a single process, the better.

    Chip makers have for ages been using a single chip and making minor mods to create different products. The old Intel Celeron was just a Pentium with some cache disabled. A Core i7 920 and 975 Extreme are essentially the same chip, the 920 just has a small, locked multiplier while the much more expensive extreme just has an unlocked multiplier.

  • 0 Hide
    Silluete , February 23, 2009 7:55 PM
    If this new true aren't AMD gonna do something? or at least asking biostar to change the bios
  • 4 Hide
    jerreece , February 23, 2009 7:59 PM
    Assuming this is true, it could be bad for AMD's quad core sales. ;)  Why pay more for a quad core, if you can buy a tri-core and potentially "unlock" the 4th hidden core?


    Sort of amusing. But I guess it does sort of make sense. But the fact that simply setting "Auto" on your motherboard causes the 4th core to activate would suggest AMD didn't do a very good job in disabling the potentially bad core.
  • 0 Hide
    eddieroolz , February 23, 2009 8:00 PM
    That's neat! I'd so get a Phenom II right now..
  • 0 Hide
    Greg_77 , February 23, 2009 8:17 PM
    If these processors turn out to be stable, you will see many budget machines built on this processor in the hope they get a quad core capable processor. Lets hope AMD doesn't disable this new "functionality".
  • 0 Hide
    blackpanther26 , February 23, 2009 8:35 PM
    I think AMD did this on porpose. Maybe this is AMD's ace? But you are taking a risk on enabling the 3rd CPU core. You may get one that would work fine but then again, you might get one that can't be stable at all even at 1GHz. But for $125.99 you are getting a bargan if you can get it to 4 cores but if not you still have a good CPU. I hope AMD keeps it this way and have a option in their AM3 boards to enable the 4th core. But as for me. I'm set with my Q9650. But I may try this out sence I have a 790GX motherboard (Foxconn). And see if it works.
  • 2 Hide
    oicw , February 23, 2009 8:50 PM
    68vistacruiserIt's interesting to see that AMD makes so many bad quads that they have a plan for selling them as triples. Kind of makes me wonder about their manufacturing quality. At least I won't have to worry about it, I don't fall for the AMD hype anymore.

    Or, you could turn around and say, wonder how much cash Intel is throwing down the drain by junking all the chips that don't have 100% stability on all 4 cores. (though right now it seems that Intel just might have that kind of money to waste...)

    I also agree w/ blackpanther that AMD probably don't care whether or not we try to enable the 4th core. At best this may actually help their sales from people willing to experiment with things. People who actually NEED a quad core will still buy quad cores, as an X3 has absolutely no gurantee the 4th core would work.
  • 2 Hide
    nekatreven , February 23, 2009 8:52 PM
    reminds me of the days of turning the radeon 9500 pro into a regular 9700.

    AMD probably wouldn't have made the X3 line if none of the chips had an actual bad core. So be aware that this may be a great way to destroy an X3 if it really did have a bad core.

    More than a few people turned a good, fast 9500 into a garbled, artifact spitting, unrecognizable 9700 by enabling 4 bad pixel pipelines with a softhack.
  • 0 Hide
    tipoo , February 23, 2009 9:17 PM
    Kind of reminds me of the whole turning a thorton into a barton thing.
  • 1 Hide
    Anonymous , February 23, 2009 9:20 PM
    guys, AMD do a lot more in testing than just chuck Prime on each core for a few hours to see if its all good. Its very likely that a defective core could work fine in 99.99% of use, but AMD has disabled it because it failed in that one small special case that most people won't ever experience. Also reminds me of the Applebred Durons a few years ago that had 64kB of L2 cache. The cores themselves were simply Thortons with a large chunk of the L2 cache disabled. Pencil modding most of the time gave you a full Thorton processor, but sometimes it;d give you a brain dead CPU. Making money out of what would otherwise be garbage makes financial sense.
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